public class Code1{
    public static void main(String args[]){
        int num[] =new int[]{2,7,11,15};
        int b =9;
        int a=0;
        for (int i= 0;i<4;i++){
            for (int j = i+1; j<4 ;j++){
                a=num[i]+num[j];
                if(a==b){
                    System.out.print(i);
                    System.out.print(j);
                    }
                
                }
            }

        }
        
    }
    
